Airworthiness Directive · Amendment 39-22009 · Turbine engine compression section
General Electric Company Turbofan Engines
This AD applies to General Electric Company (GE) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model turbofan engines installed on an airplane that has accumulated 250 or more parked days outdoors within the 24 months prior to the effective date of this AD.
The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) CF34-8C and CF34-8E model turbofan engines. This AD was prompted by an "Engine Degraded" message received in-flight from the Engine Indicating and Crew Alerting System (EICAS), and a subsequent investigation by the manufacturer that revealed corrosion of the variable geometry (VG) system actuator, which can cause the full authority digital engine control (FADEC) software to command and lock the engine at idle until it is restarted. This AD requires performing a rotational torque check on the actuating linkage assembly and, depending on the results of the rotational torque check, replacement of the compressor inlet guide vane (IGV) outer shroud bushing and vane spindle bushing with parts eligible for installation. This AD also requires reporting the results of the rotational torque check to GE. The FAA is issuing this AD to address the unsafe condition on these products.
(i) If the affected engine is installed on an airplane that was parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, within 30 flight hours (FHs) or 5 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 440 FHs after the effective date of this AD.
(ii) For affected engines not requiring the performance of a rotational torque check by paragraph (g)(1)(i) of this AD, if the affected engine is installed on an airplane that was parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, within 200 FHs or 35 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD.
(iii) For affected engines not requiring the performance of a rotational torque check by paragraphs (g)(1)(i) or (g)(1)(ii) of this AD, before exceeding 880 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 1,680 FHs after the effective date of this AD.
(i) If the affected engine is installed on an airplane that was parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, within 200 FHs or 35 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD.
(ii) For affected engines not requiring the performance of a rotational torque check by paragraph (g)(2)(i) of this AD, if the affected engine is installed on an airplane that was parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, before exceeding 440 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD.
(iii) For affected engines not requiring the performance of a rotational torque check by paragraphs (g)(2)(i) or (g)(2)(ii) of this AD, before exceeding 880 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 1,680 FHs after the effective date of this AD.
If the affected engine is installed on an airplane that was parked outdoors for 250 or more parked days within the 24 months prior to re-entering service, or if the engine was off-wing and stored outdoors for 250 or more days within the 24 months prior to reentering service, before further flight, perform a rotational torque check of the actuating linkage assembly.
If the actuating linkage assembly does not pass any rotational torque check required by paragraphs (g)(1) through (3) of this AD, before further flight, remove the compressor IGV outer shroud bushing and vane spindle bushing and replace with a zero cycles since new compressor IGV outer shroud bushing and vane spindle bushing.
Use the Accomplishment Instructions, paragraph 3.A.(1)(c), of GE CF34-8C Service Bulletin (SB) 72-0356 R00 or GE CF34-8E SB 72-0244 R00, both dated February 15, 2022, as applicable to the engine model, to perform the actions required by paragraphs (g)(1) through (4) of this AD.
Within 10 days after performing the rotational torque check required by paragraphs (g)(1) through (3) of this AD, in accordance with paragraph 3.A.(1)(c), of GE CF34-8C SB 72-0356 or GE CF34-8E SB 72-0244, send your inspection report form, pictures, or report findings to GE at aviation.fleetsupport@ge.com.
(1) For the purpose of this AD, a “parked day” is 24 consecutive hours without engine operation.
(2) For the purpose of this AD, “outdoors” is any location that is not environmentally controlled, including any non-environmentally controlled facility.
